It is widely accepted that public relations emerged as practice and as a profession by the end of 19th century and more distinctly with Edward Bernays. Sigmund Freud being his uncle added a salt to this myth and a book Crystallizing Public Opinion (1923) marks a kind of theoretical foundation of a profession.
There are two ways how to handle this myth. One way historical. Historians track down examples that could be understood as public relation practice and even PR consultancy profession back to most ancient times. It is not wrong to entertain with historical stories (as we should know by now, facts by definition do not constitute history), but it makes as much sense to prove public relations is ancient practice as to track back in history when blood appeared in human bodies. Society cannot exist but through public relations.
Metabolic background of public relations
Public relations are a fundamental feature of every living creature. As it is true that a living creature is defined in relation (as it borders) to its surroundings through metabolic functions, it is true that any social organization is only defined in relations (as it borders) to consumers and publics.
Social organizations are metabolic. Each individual part of such organization receives something from another individual and gives him something that another is in the need of. Such exchange goes down to plants and viruses if you wish. But goes also up to ants that already exchange information for the sake of their collective social structure. Further up (in higher vertebrates and especially among humans) information transform into meme, memes and meme-complexes. As we now know memes live their own selfish lives (this makes them different from information), but this fact is not so important for the case of public relations. What is important is that if exchange of information/memes is important then such activity has to be managed this way or another.
Memetic creatures thus perform memetic relations with their environment by definition, unconsciously. But as we breath unconsciously most of the time, there are moments when we consciously manage our breathing. Similarly, we communicate (note that breathing is a part of non-memetic relation to environment) with environment mostly unconsciously, but there are times when even individuals have to manage communication consciously.
Further up, when we come to more complex social entities that behave like living entities with distinct identities (brand qualities), like companies, municipalities, states, etc., a question arises whether public relations functions enact themselves consciously or unconsciously. Namely if we know that each living entity has its own “public relations” (selfish) agenda (will), and that such property is found on genetic level as much as on the level of complex social structures that are defend as brands, does that mean that lower and higher entities than humans perform their PR functions consciously or unconsciously?
Private and impenetrable
The answer is in fact quite simple but important. No. We can speculate whether other living creatures possess consciousness or not, but even if they did, it would remain impenetrable for us humans. Consciousness is fortunately 100% private. For that reason, we have to separate all other characteristics of living creatures from it. Genes have all possible metabolic functions including will, but consciousness. As the matter of fact consciousness is the only property of living creatures that is not metabolic and thus also not relational. For that reason, it is also the only function that can manage something outside itself. For that reason, all living entities form genes to large social structures act and react, but only humans manage.
Public relations are thus one of the key business functions of any type of organization that are both enacted and managed. They are enacted by organizations that for this or that reason do not care to manage them. If they are enacted, they are enacted unconsciously, without conscious involvement of humans that are part of that organization.
We can thus say that public relations as enacted practice is as old as the oldest social structures or as long as memes appeared as second replicators. But since consciousness is 100% private feature it is by definition impossible to assess when public relations became conscious, managed practice. Artefacts like written records or any other artefacts prove that acts behind those records were conscious, but they say nothing about all other historical enactions that might as well be conscious/managed.